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  • Wort Chiller Care and Maintenance

    I recently took apart my plate chiller after over a year of operating a 10BBL brewhouse. Yes, it was disgusting, but I started wondering, how do other breweries clean theirs? How do they store them? Surprisingly, I could find no real thread dedicated to caring for these vital pieces in everyone's brewhouse. Ours is a 77 plate chiller that is a BEAR to clean. We soaked the whole thing in caustic, gaskets and all, then scrubbed the gunk off of them one at a time. Then, they went into an acid batch. Had a final scrub and rinse, and are about to be reassembled.

    My question is, what is a good cleaning regiment? What should I pump through after each brewday? What special care should I give it?

    I've heard (and done) so many things about this so please contribute! I've even heard brewers storing it in acid in between brewdays and things like that, I've even heard some brewers refuse to take it apart ever! Others still just run water in a backflush, which from empirical evidence, is definitely not doing much in our brewhouse.

    Before I sacrifice a nice chiller to a stupid idea, I need info! Come on forumites! Don't let me down!

  • #2
    This is what I do in terms of care of my chiller. I'm not sure its the best way to go about it, but the last time I had to take apart my chiller (I had a gasket start leaking) things were clean.

    When I brew I'm running hot water (190+) through the chiller for 15+ min to make sure it is fully pasteurized.
    After knocking out through the chiller I rise in the forward direction with hot liquor - and I make sure that the outlet valve on the HX is opened and closed (this puts some pressure on the plates and helps loosen chunks.
    Once the water coming out of the chiller seems clean and clean I look up for my CIP.
    I alternate my brewhouse CIP between caustic and PBW. I run a 20 min cycle in the reverse direction of normal flow, again opening and closing a valve to put pressure on the plates.
    When I run caustic I then follow with an acid rinse. When I clean with PBW I leave the HX packed with PBW until the next brew.
    Manuel

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    • #3
      After brewday on a 20 BBL system (varies between one or two batches a day, two days a week):

      - Hot rinse until clear (forward)
      - 3% caustic @ 160F for 45 min (forward)
      - Hot rinse (forward)

      Once a week:

      - Hot rinse to preheat chiller
      - 3% caustic @ 160F for 45 min (forward)
      - Hot rinse (forward)
      - 3% nitric acid @ 140F for 45 min (backward)
      - Hot rinse (backward)

      Try to maintain temperature during CIP and keep pump speed slightly higher than what you would run at knockout.

      Comment


      • #4
        Here is what we do:
        Brew Day:
        Flush PAA backwards through heat exch. (from sanitized FV we are brewing into) out bottom of BH manifold.
        After Brew:
        Backflush w Alkaline Cleaner through heat exchanger from kettle back through kettle sprayball. +/-45 minutes at twice the speed we knocked-out wort forward through heat exchanger.
        Hot water rinse at same speed for +/- 5 minutes.
        Forward flush with PAA from kettle at knockout speed.
        Before pump is turned off, pinch heat exch drain valve to pack with PAA, and leave packed w PAA until next brew day.

        Once a month, we run an acid cycle forward through the heat exchanger, and then through the back side of the plates as well, to combat scaling from cooling water.

        Hope this helps, cheers!

        Comment


        • #5
          The key factor that many setups do not allow for is adequate pipeline and PHE cleaning speeds. Wort and veer have to be run at barely turbulent flow rates, whereas to clean the same pipe / PHE, generally much higher speeds are required. Typically PHE packs are designed to be cleaned at 1.3 to 1.5 times the design product forward flow rate. Twice is nice to have, but in a large brewery, this would increase energy costs and possibly pressure too much for safety, but in a small brewery, this is less likely to be a problem. Back cleaning is preferred as it pushes solids stuck near the start of cooling phase back out, more easily, than having to push through the bulk of the PHE.

          If you are using a suitably formulated caustic at suitable strength - commonly circa 2%, then acid washes should not be required on a regular basis. If they are required it is because the chemicals are not formulated to cope with the mineral composition of the wort. I have worked in breweries where the PHE doesn't get stripped apart for years, but cleaning direction and frequency, chemical composition and speed are critical to allow this.
          dick

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          • #6
            What I've found

            Thanks for all the suggestions. I think what we started doing is similar.

            Before a brew:
            -Flow whatever cleaner is used in the fermenter (sometimes saniclean, sometimes not. We have plastic fermenters as well as stainless, so it varies) through the plates until the fermenter is just about empty, then close the backside valve and let it soak in sanitizer until whirlpool is complete.
            -Flow wort through without cooling water flowing until I see it come out the back
            -Hook up my hoses and fill a fermenter

            After a brew:
            -Back Flush 185 degree water For about 60 seconds (unless it's still not clear)
            -Back flush with cool water for 60 seconds
            -Circulate 170 degree caustic solution for 10-15 minutes backwards at a much higher speed than knockout (valve all the way open and pump at full speed) which we recirc through the mash tun since we're still cleaning hot break and gunk out of the boil kettle.
            -Then it gets rinsed a couple times with hot water.
            -If we're brewing the next day, that's about it.
            -If we're not brewing, we do all of the above and then pack the plates with an iodophor solution to avoid any long-term acid contact. Sometimes we go a week without brewing, so I don't feel comfortable leaving any harsh ph chemical in there for long. (i.e. what happens when the assistant leaves a valve in a caustic or acid solution over night by accident).

            As far as extensive maintenance, I don't see a need to ever FULLY disassemble the unit again, but perhaps loosen it up and visually inspect/spray it out when the plates are separated, but still hanging on the frame.

            So far, it seems the commonalities are many, but the methods we might specifically use are different.

            I hope people will keep contributing to this thread so other brewers have something to reference.

            Comment


            • #7
              There are other threads referencing problems associated with stripping plate packs. I suggest you look at those, including this one - HX breakdown frequency?
              dick

              Comment


              • #8
                Everyone is saying to run the acid/caustic/alkaline cleaner phase at 1.5 to 2 times the speed of knockout through the PHE. When we're knocking out I'm pretty much maxing my pump out and we're done in 25 minutes. This means at max the acid/caustic/alkaline cleaner phase is exactly the same speed as during knockout-or less. Should I be running my wort pump during knockout at a much slower speed so that when we're running the various cleaning cycles on the PHE it's going much faster than the wort is during knockout? I was under the impression it was best to knockout as fast as your PHE can cool the wort.

                Comment


                • #9
                  No. What is being said is that the PHE is designed to cool wort from x to y at flow z, with cooling water flow of a, cold temperature of b and hot temperature of c. So the PHE should have been designed for wort cooling flow rates. If you are achieving the parameters as above, then you are running wort at the correct (design) flow rate. The CIP flow rate is typically 1.3 to 1.5 times the design flow rate for cooling. However, for effective cooling, the wort (and cooling water) flow rates should be high enough to create turbulent flow in the PHE, so providing the CIP flow rate is no less than the wort cooling design flow rate, you should be OK.
                  dick

                  Comment


                  • #10
                    Just notice this as part of an earlier comment

                    "If we're not brewing, we do all of the above and then pack the plates with an iodophor solution to avoid any long-term acid contact"

                    DON'T DO THIS if you want your chiller to last. Iodophor contains iodine, one of the same series of elements as chlorine (in the periodic table of elements, which all have similar characteristics to some degree). I have seen it used in stainless soak baths, and the end result has been holes in the soak bath, holes in the stainless fittings left soaking in the iodophor solution and severe damage due to corrosion of the brass nuts used instead of stainless nuts in that particular company (big advantage - no stainless to stainless seizing making cutting off the only solution), due to the acid content dissolving the copper and zinc. Iodophor is reasonably stable, but only really active as a sterilant in an acidic solution, which means pitting corrosion and in items like PHEs, stress corrosion cracking can take place. It is almost as destructive as chlorine.

                    You shouldn't need to leave soaking under anything because if you leave it for that long, you should reclean / resterilise before wort transfer. If you want to leave under sterilant, then use PAA - 150 to 250 ppm.
                    dick

                    Comment


                    • #11
                      We were doing a light cleaning on our HX daily, and a through cleaning every 2 months. This resulted in needing to break open the plate pack once a year.

                      Light cleaning=
                      Back flush with Hot H2O, low pressure for 15 minutes
                      push 15 gallons of hot caustic solution with an oxidizer/surfactant in, and let sit for 5 minutes.
                      push 15 more gallons of the same as above and repeat for 5 more minutes.
                      push 30 gallons of Hot H2O through as fast as the pump would go without cavitating.
                      push 15 gallons of a weak (.75%) nitric/phosphoric acid solution in and lock it.

                      our heat exchanger never sat for more than 3 days between use.

                      Full CIP=
                      flush with hot both directions at high pressure till water coming out is totally clean.
                      Cycle caustic and oxidizer/surfactant solution through the HX for 10 mins.
                      dump rinse and repeat above in opposite direction for 10 mins.
                      Repeat above until no more color change is seen during cycle.
                      rinse thoroughly in both directions, run a 10 minute 2% nitric phosphoric acid solution through the exchanger and then through the water plates as well.

                      This got us to about a year before we would see decreased chilling ability (longer knockouts to maintain the same temperature as before). Then I changed one small stupid little thing and we have never needed to pull the HX plates apart ever again. I even checked after the first year to see if it was working. The plates used to be gross and all caked up, this time they were damn near spotless, ran this way for the past 2.5 years without the need to break down the plates in that time.

                      The only change was during the back flush at the start of the light cleaning I would bubble compressed air as lightly as possible through the aeration stone just after (or just before when running backwards) the heat exchanger. Obviously your mileage may vary but I'd give it a shot. All that air is giving you far better mechanical action than almost anything else you can do.

                      Comment


                      • #12
                        Originally posted by BDL View Post

                        The only change was during the back flush at the start of the light cleaning I would bubble compressed air as lightly as possible through the aeration stone just after (or just before when running backwards) the heat exchanger. Obviously your mileage may vary but I'd give it a shot. All that air is giving you far better mechanical action than almost anything else you can do.
                        Can you explain what you mean by this? You're bubbling air through the HX post pump or pre? Is this during pumping? After? I know I've tried blasting out the HX with co2 before but that was greed trying to fill a fermenter and get every last drop. It sounds like you're aerating the caustic? I don't see why that would help so please enlighten me.

                        Also, for the record. I have repented of using iodine. That was bad advice given to me and then passed on by me. Apologies. It will pit stainless over time. I agree with previous comment about PAA at a light dilution or nitric at a light dilution. But I have since just cleaned it again. My goal wasn't to prevent having to clean again, but make the cleaning more efficient, ya know, keep as many bugs, crap, smelly stuff out of the plates for as long as possible.

                        Comment


                        • #13
                          "...... I would bubble compressed air as lightly as possible through the aeration stone .......". What a great idea!

                          Re the process - CIP tank --> pump --> wort main at FV --> aeration stone -> PHE --> CIP tank

                          The point about H2O2 is that the heat of the caustic solution generates oxygen bubbles doing two things, one is to increase the turbulence / scouring action of the caustic, and secondly, the hot oxygen oxidises the residues, making them easier to remove. I am sure H2O2 would have a greater oxidation effect, but this method sounds so much cheaper and safer to handle. I'd love to be able to try it on a big brewery setup as well.

                          It is the mix of liquid and gas that is critical. Gas on its own is useless at removing this sort of gunk in a PHE, though I have seen developments using higher volumes of gas and only a little liquid for cleaning pipes, though I am not sure how effective they are in a brewery, and anyway, you have to purge out the mains etc with water or gas before beer transfer, which negates a lot of the systems value.
                          dick

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